Rotary fluid pressure pumps and motors of the eccentric vane type



y 18, 1965 D. H. COCKBURN 3,133,843

ROTARY FLUID PRESSURE PUMPS AND MOTORS OF THE ECCENTRIC VANE TYPE FiledApril 22, 1963 V 4 Sheets-Sheet 1 IN VE N TOR fin wp hnmLra/v COCKBURN ATTORNEY y 13, 1965 D. H. COCKBURN 3,183,343

ROTARY FLUID PRESSURE PUMPS AND MOTORS OF THE ECGENTRIC VANE TYPE FiledApril 22, 1963 4 Sheets-Sheet 2 INVENTOR M MM ATTORNEY BURN 3,183,843PUMPS AND MOTORS C VANE TYPE May 18, 1965 D. H. COCK ROTARY FLUIDPRESSURE THE ECCENTRI 4 Sheets-Sheet 3 Filed April 22, 1963 IN VE N TORfl/W/o Han/a0 [burs amv A TTORNE Y D. H. o BURN 3,183,843 ROTARY FLUIDPRE S PUMPS AND MOTORS OF THE ECG IC VANE TYPE Filed April 22, 1963 May18, 1965 4 Sheets-Sheet 4 IN 5 N TO}? 17/11/10 f/nmLravCocwz/xw ATTOP/Vf Y United States Patent 3,183,843 ROTARY FLUID PRESSURE PUMPS ANDMOTORS OF THE ECCENTRIC VANE TYPE David H. Cockburn, 1 N. Park, Iver,Buckinghamshire, England Fiied Apr. 22, 1963, Ser. No. 274,530 4 Claims.(Cl. 103-136) This invention relates to rotary fluid pressure pumps andmotors of the eccentric vane type, such pumps or motors including acasing defining a substantially cylindrical working chamber having inletand outlet passages leading to inlet and outlet ports, the chambercontaining an eccentrically mounted rotor, said rotor carrying a seriesof substantially T shaped vane elements or slippers which move radiallyin relation to the rotor whilst r0tating therewith, their outer surfacesmaintaining contact with the inner wall of the working chamber in asubstantially fluid tight manner.

The present invention is virtually an improvement in or modification ofthat forming the subject of my prior U.S. Patent No. 2,778,317.

The chief object of the invention is to increase the capacity of suchpumps and motors and particularly the pump or motor forming the subjectof the above numbered patent and when operating as a motor to give anincreased torque.

In the earlier patent above referred to, the slippers converged towardsone another over that part of the wall of the working chamber lyingnearest to the axis of rotation of the rotor and consequently the lengthof the transverse portions or flanges of the T shaped slippers waslimited and there was considerable spacing of the flanges, over thatpart of the chamber wall lying furthest from the axis of rotation. Thislimitation in the length of each flange limited the ratio between thelength of each flange and the length of the intermediate inwardlydirected stern and if this ratio was reduced to less than 2-1 there wasrisk tilting of the slippers occurring and the break ing down of theseal between the slippers and the wall of the working chamber.

The present invention consists broadly in so constructing the slippersthat the flanges of adjacent slippers overlap one another in a lateraldirection. In this way the effective length of each flange isconsiderably increased and it is possible to increase the length of eachstem, thus decreasing the risk of tilting and enabling the eccentricityof the rotor to be considerably increased over and above theconstruction previously proposed. Furthermore by employing flanges ofgreater length the hydraulic load between each slipper and the wall ofthe working chamber will be substantially decreased.

Such an arrangement very materiallly increases the capacity of the pumpor motor and in the case of a motor considerably increases the outputtorque available without adding to the friction and leakage lossesthereby pro viding a considerable increase in overall efliciency.

Referring to the accompanying drawings:

FIGURE 1 is a view, halt section and half elevation of a pump or motorfitted with slippers and a rotor in accordance with the presentinvention;

FIGURE 2 is a section on the line A--A in FIGURE FIGURE 3 is a sectionthrough the centre of the improved slipper; and

FIGURE 4 is a development illustrating how two of the slippersinterengage;

FIGURE 5 is a side elevation of one of the assembled helical and flatsprings for urging the slipper outwardly into engagement with thecircumferential wall of the working chamber;

FIGURE 6 is a plan view of the helical spring;

"Ice

FIGURE 7 is a plan view of the flat spring;

FIGURE 8 is a half sectional, half eleva-tional view of the casing;

FIGURE 9 is a half sectional plan;

FIGURE 10 is a vertcial section on the line B-B in FIGURE 8;

FIGURE 11 is a section on the line CC in FIGURE 12 showing .theinvention applied to a modified pump or motor of variable stroke; and

FIGURE 12 is a half elevational, half sectional view of same.

Referring in the first case to FIGURES 1 and 2, the pump or motorcomprises a casing 1 having an annular boring constituting thecircumferential wall of the working chamber which is closed at its endsby end plates 2 and cover plates 3, the end plates carry-ing bearings 4for .a rotor shaft 5 carrying in splined connection a rotor 6 formedwith for example five flat faces 7 separated by slots 8, the walls ofwhich diverge radially inwardly. The shaft is eccentrically mounted sothat the rotor 6 rotates eccentrically within the working chamber.

The casing 1 is provided with inlet and outlet passages 9 for theworking fluid communicating with the working chamber.

The rotor 6 carries for example five slippers 10 which are exteriorlycurved to conform to the internal curved surface of the working chamber.

The general formation of the slippers is illustrated more clearly inFIGURES 3 and 4, each slipper including a central stem 11 which entersone of the slots 8, the stem having a thickness such that it fitsclosely within the mouth of the slot, but is free to pivot thereinduring rotation of the rotor, the edges of each slot adjacent the mouthbeing radiused as shown in FIGURE 1.

Each slipper includes a pair of flanges of fork shape and each includinga pair of tapering tines or fingers indicated by reference numerals 15and 16.

Times 15 have parallel outer edges 17 and inclined inner edges 18.

Tines 1-6 have outer edges 19 inclined to correspond with theinclination of edges 18 so that adjacent slippers overlap laterally inthe manner shown in FIGURE 4 leaving only a small working clearancebetween them.

The inner edges 20 of tines 16 are arranged in parallel relationship andallow the passage of the working fluid therebetween into and out of theworking chamber.

Each fork is bevelled as at 21 to give increased lap relative to theinlet and outlet passages for the fluid and at the same time permit ofuniform deflection of the tines under load conditions, the tines byvirtue of their resilient construction making resilient engagement withthe wall of the working chamber.

Although it is preferred to construct the slippers as drop forgings theymay alternatively be bent up from sheet metal blanks, each slipper beingconstructed as two parts of substantially L shape, each including a halfstem portion and a flange portion, the half stem portions being rivetedor otherwise connected together back to back to form a complete stem.

The slippers are maintained in working engagement with the wall of theworking chamber by spring assemblies shown in FIGURES 5 to 7, eachassembly consisting of a helically wound spring 12 and a flat spring 13,the latter having a pair of arms projecting in opposite directions froma central loop 14 for the reception of a rivet 15' passing through anend loop 16 on the helical spring whereby the two springs are securedtogether.

Each assembly is mounted in the position shown in FIGURES 1 and 2, eachhelical spring being located in a recess 22 by a spigot portion 23, theflat spring bearing on the laterally overlapping tines of adjacentslippers to urge them radially outwardly into engagement with the wallof the working chamber. Only one such spring unit 12, 13 is shown inFIGS. 1 and 2.

The positioning and shape of the ports leading from the working chamberto the inlet and outlet passages 9 is shown more clearly in FIGURES 8 to10. The casing contains a pair of oppositely positioned arcuate shapedmain ports 24 and two pairs of correspondingly shaped side ports 25, thelatter being connected with inlet an outlet passages 9 by branchpassages 26.

FIGURES 11 and 12 illustrate a construction of .pump or motor whereinthe degree of eccentricity of the rotor and consequently the effectivestroke of the slippers can be varied, to vary the effective capacity ofthe pump or motor and in the case of a motor to reverse its direction'of rotation, and in the case of a pump reverse the direction of theflow of fluid.

The casing 1 is extended upwardly and downwardly to enclose the inletand outlet pipes 9 and 9a, the casing 7 being pivotable about the axisof pipe fi through a limited angle in opposite directions from a centralneutral position in which the rotor is concentrically positioned in theworking chamber in which position there will be no displacement of theslippers and consequently no fluid displacement or in the case of amotor no rotation of the rotor. By moving the casing in one directionfrom the neutral position to its maximum angular position an infinitelyvariable output or in the case of a motor a variable rotor speed can beobtained, the direction of fluid flow or rotation of the rotor beingreversed by moving the casing in the opposite direction.

Any suitable means may be used to move the casing about its pivot pointwhilst the pipe 9a enters the casing through an elongated hole 27, thepipes 9 and 9a being formed with a series of radial holes 28 in theirwalls through which the fluid can enter and leave the casing. It will beappreciated that only the casing will partake of the pivotal movement,the casing having a combined sliding and pivotal movement between thetwo fixed cover plates 2, the facesof the casing being formed withgrooves containing sealing members 29, for preventing leakage of fluidbetween the ground faces of the casing and cover plates.

I claim: 1. In a hydraulic pump or motor of the type comprising a casingdefining a substantially cylindrical working chamber with acircumferential wall and two end walls and a rotor mounted eccentricallywithin said casing, said rotor having a plurality of spaced groovesextending longitudinally and radially inwardly from the circumferencethereof, the improvement comprising a series of slipper elementscorresponding in number to the number of said spaced grooves and adaptedto slidably engage the circumferential wall of the cylindrical workingchamber,

each of said slipper elements having a stem portion slidably extendinginto its particular groove so as to move in and out of said groove,

each of said slipper elements having a first pair of fingers curved tofit the contour of the cylindrical working chamber extending forwardlyfrom said stern, and a second pair of fingers curved to fit the contourof said cylindrical working chamber extending to the rear of said stem,

the second pair of fingers of any slipper element of said seriesinterfitting with the first pair of fingers of the next adjacent slipperelement while providing openings for the passage of fluid between saidsecond pair of fingers.

2. The pump or motor as claimed in claim 1 wherein said first pair offingers of each slipper element have parallel outer edges but divergeoutwardly from their innerends to provide a diverging slot therebetween,said second pair of fingers having converging outer edges adapted to fitwithin the diverging slot between the first pair of fingers of the nextadjacent slipper element.

3. The pump or motor as claimed in claim 1 wherein the connectionbetween the stems of said slipper elements and the fingers thereof istapered.

4. The pump or motor as claimed in claim 1 wherein said rotor containsat least one recess between adjacent spaced grooves,

spring means having one end thereof retained within said recess and theother end thereof pressing against the interfitting first and secondfingers of two adjacent slipper elements.

References Cited by the Examiner UNITED STATES PATENTS 713,448 11/02Kalbach 91-134 1,333,656 3/20 Eizerman 103135 2,336,580 12/43 Yeatman103l17 2,778,317 1/57 Cockburn 103134 FOREIGN PATENTS 737,292 7/43Germany.

JOSEPH H. BRANSON, JR., Primary Examiner.

1. IN A HYDRUALIC PUMP OR MOTOR OF THE TYPE COMPRISING A CASING DEFININGA SUBSTANTIALLY CYLINDRICAL WORKING CHAMBER WITH A CIRCUMFERENTIALLYWALL AND TWO END WALLS AND A ROTOR MOUNTED ECCENTRICALLY WITHIN SAIDCAING, SAID ROTOR HAVING A PLURALITY OF SPACED GROOVES EXTENDINGLONGITUDINALLY AND RADIALLY INWARDLY FROM THE CIRCUMFERENCE THEREOF, THEIMPROVEMENT COMPRISING A SERIES OF SLIPPER ELEMENTS CORRESPONDING INNUMBER TO THE NUMBER OF SAID SPACED GROOVES AND ADAPTED TO SLIDABLYENAGAGE THE CIRCUMFERENTIAL WALL OF THE CYLINDRICAL WORKING CHAMBER,EACH OF SAID SLIPPER ELEMENTS HAVING A STEM PORTION SLIDABLY EXTENDINGINTO ITS PARTICULAR GROOVE SO AS TO MOVE IN AND OUT OF SAID GROOVE, EACHOF SAID SLIPPER ELEMENTS HAVING FIRST PAIR OF FINGERS CURVED TO FIT THECONTOUR OF THE CYLINDRICAL WORKING CHAMBER EXTENDING FORWARDLY FROM SAIDSTEM, AND A SECOND PAIR OF FINGERS CURVED TO FIT THE CONTOUR OF SAIDCYLINDRICAL WORKING CHAMBR EXTENDING TO THE REAR OF SAID STEM, THESECOND PAIR OF FINGERS OF ANY SLIPPER ELEMENT OF SAID SERIESINTERFITTING WITH THE FIRST PAIR OF FINGERS OF THE NEXT ADJACENT SLIPPERELEMENT WHILE PROVIDING OPENINGS FOR THE PASSAGE OF FLUID BETWEEN SAIDSECOND PAIR OF FINGERS.